1. Field of the Invention
The present invention relates to a display apparatus provided with an organic electroluminescent element.
2. Description of the Related Art
The organic electroluminescent element has a configuration in which an anode, a light-emitting layer containing an organic compound, and a cathode are stacked. Regarding a display apparatus including organic electroluminescent elements of three colors, red, green, and blue, a light-emitting layer of each color is vacuum-evaporated by using a metal mask for patterning in accordance with the pixel shape of the color concerned.
In recent years, each color pixel size has been reduced along with an improvement in accuracy of the display apparatus, and a high degree of accuracy has been required with respect to the metal mask for patterning in accordance with the pixel shape. Consequently, the proportion of the metal mask cost in the production cost of a display apparatus has increased and, thereby, production and maintenance of a metal mask have become difficult.
Japanese Patent Laid-Open No. 2007-066862 discloses a technology in which a blue light-emitting layer having a low luminous efficacy is disposed all over a pixel region and a red light-emitting layer and a green light-emitting layer are stacked in the side nearer to a take-out electrode than is a blue light-emitting layer. It is stated that the blue light-emitting layer having a low luminous efficacy is formed all over the pixel region to increase a blue pixel area and, thereby, the number of usage of the metal mask for patterning is reduced and the life of the display apparatus can be improved.